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PRIMARY GEAR FRONT FLOATING BUSH 1275cc
C-AEA3240 In stock
This is our racers' preferred solution for handling worn or problematic front primary gear bushes. (Note: this is NOT the top hat type rear bush.) Width: 22.5mm. While professional engine builders and racers may use their own tolerances, these bushes are set for road use.
**Please Note:** This floating bush is not suitable for early Cooper S primary gears, which have larger internal diameters, original A+ helical primary gears, or our own straight-cut primary gears manufactured before 2015. It is compatible with Minispares-produced helical gears and straight-cut gears made after 2015.
Ideal for use with stepped type 1275cc cranks, this fully floating bush eliminates the need for additional fitting or machining costs. Always ensure the bush seats squarely against the shoulder with the oil holes aligned properly in the trough, avoiding the edge of the stop step—since oil drain holes can act as cutting edges on the bush.
Remove the old bush and clean the area with wet and dry abrasive. Check that the inner bush area is not machined at an angle near the oil hole, as this can damage the new floating bush—a common machining trait of most A+ gears. After cleaning, insert the pre-oiled bush, and you're ready to go.
Ensure the crankshaft is free of wear or blemishes.
Developed by Minispares' technical team, this bush has an ID of 1.628" +0.002" –0.0", never undersized to maintain proper clearance. For racing applications, allow an extra thou (ID: 1.504" +0.001"). The gear's ID is 1.750"; our bush measures approximately 1.748" ±0.5 thou.
Measurement details (2024):
- Outer diameter: 44.40/44.38mm
- Inner diameter: 41.375/41.34mm
- Length: 22.50mm
See C-AEA3241 for a shorter version of this bush with a length of 19.85mm.
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